In the past, there have been proposals of a three-dimensional forming device (commonly known as a 3D printer) which forms a three-dimensional object by an inkjet method, and a water jet method for removing by water-spraying pressure, for example, has commonly been used as the method for removing a support material on the surface of a three-dimensional object formed by this three-dimensional forming device. However, the problems with this method are that the support material cannot be sufficiently removed (some slipperiness remains on the surface of the three-dimensional object), large-scale equipment is needed such as high-output pumps and pipes for wastewater treatments, and high costs are incurred.
In view of this, a method (hereinbelow the conventional method) of soaking a three-dimensional object in a chemical solution to remove a support material has been proposed as disclosed in JP-A No. 2011-5667, for example, and the support material can be removed more satisfactorily in comparison with the previously described water jet method.